Hydroxyethyl starch solutions and their effect on the microcirculation and tissue oxygenation*

Abstract

SUMMARY The main goal of ideal fluid therapy is not only to maintain systemic circulation, but also to restore tissue perfusion and oxygen delivery to the tissues and specifically to the microcirculation where oxygen delivery takes place. For this purpose, various kinds of crystalloid and colloid solutions are being used. The ongoing debate about the use of crystalloid versus colloid solutions has now shifted to a debate on the ideal type of colloid solution. Hydroxyethyl starch (HES) is one of the most studied plasma substitutes. Different kinds of HES solutions exist worldwide, which differ greatly in their pharmacological properties. Low‐molecular‐weight HES solutions have been successfully and safely used for intravascular volume therapy, and also to restore hemodynamic, microcirculatory and cardiorespiratory function. This article reviews their effect on the microcirculation and tissue oxygenation.

Renal Hypoxia and Dysoxia After Reperfusion of the Ischemic Kidney

“…Several lines of evidence show a difference in microcirculatory oxygenation and renal oxygen consumption between different fluid regimens (38). High-molecular-weight hydroxyethyl starch solutions (≥200 kDa) appear to be deleterious in terms of renal function (203,204); low-molecular-weight starch solutions, on the other hand, may improve renal tissue oxygenation by decreasing blood viscosity (205) and reducing vascular resistance, along with preventing starch molecule accumulation in the renal tubules and the disturbance of glomerular hemodynamics (206). Likewise, because low doses of dopamine are ineffective in terms of prevention or treatment of acute renal failure (201,207), norepinephrine (208) and vasopressin (209) are probably the drugs of choice for improving function in the renal macrocirculation and microcirculation.…”

Synthetic colloid fluids (6% hydroxyethyl starch 130/0.4 and 4% succinylated gelatin) interfere with total plasma protein measurements in vitro

“…The pharmacokinetics of HES and GELO in vivo will determine how the interference with TPP measurement changes over time after a fluid bolus. The HES fluid evaluated in this study is a polydispersed solution with a mean MW of 130 kDa and a molar substitution of 0.4, hence the nomenclature 130/0.4 . The majority of the HES molecules, smaller than the pore size of the glomerular membrane (45‐60 kDa), are freely filtered by the kidneys and excreted rapidly .…”

“…Synthetic colloid fluids are used to expand circulating blood volume in critically ill dogs . These fluids contain large molecules that range in size from low (<70 kDa) to high (>450 kDa) mean molecular weights . Synthetic colloid fluids mimic the colloid osmotic effect of plasma proteins and are often chosen for dogs that have decreased plasma protein concentrations to manage low intravascular colloid osmotic pressure (COP) .…”

Determination of the parameters of molecular-weight distribution of hydroxyethyl starches by diffusion-ordered NMR spectroscopy

“…Starches of natural origin cannot be used as plasma volume expanders, because they are rapidly hydro hydrolysis and, correspondingly, the metabolic degra dation and elimination of preparations from the blood flow [5]. The physical and chemical properties, metabolism, and excretion of HESs depend not only on the properties acquired in the hydroxyethylation of starch, but also on its molecular weight distribution (MWD).…”